This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Solution for Homework 7 Conductors and Dielectrics Solution to Homework Problem 7.1(How is Field Reduced in a Conductor?) Problem: Which of the following best describes how a conductor lowers the electric field in its interior? Select One of the Following: (a) Electric field lines cannot penetrate conducting atoms. (b) A conductor does not allow field lines through its surface. (c) The electric field causes a continuous flow of charge which upsets the field. (d-Answer) A surface charge is set up that creates an electric field which cancels the applied field. Solution (d): Charge moves to the surface of a conductor creating a net zero field inside. Total Points for Problem: 3 Points Solution to Homework Problem 7.2(Field inside Conductor) Problem: I place q = 3 C of charge on a solid copper metal marble with a radius of 3 cm. What is the electric field inside the marble? Select One of the Following: (a) 2 . 7 10 4 N C (b-Answer) 0 (c) 256 N C (d) Cannot be determined Solution The field inside a conductor is zero. Total Points for Problem: 3 Points Solution to Homework Problem 7.3(Why perpendicular to surface?) Problem: Why must the electric field be perpendicular to the surface of a conductor? Select One of the Following: (a) To make the electric field in the conductor zero. (b) Because the electric field is independent of path. (c-Answer) Otherwise there would be a component of the electric field along the surface and a surface current would flow. (d) To conserve charge. 1 Solution Otherwise there would be a component of the electric along the surface and a surface current would flow. Total Points for Problem: 3 Points Solution to Homework Problem 7.4(When is Dielectric Relation Quantitatively True?) Problem: The relation vector E = vector E where vector E is the field in the dielectric and vector E is the applied field: Select One of the Following: (a) True in all cases. (b-Answer) True only in high symmetry cases. (c) False always. Solution (b) If you look at the field map of the plastic bottle in the golf tubes electric field, the bottle alters the field in a complicated manner both interior and exterior to the bottle. The expression vector E = vector E is always qualitatively true, but only numerically or quantitatively true in high symmetry systems....
View Full Document
This note was uploaded on 03/29/2010 for the course PHYS 2469 taught by Professor Stewat during the Spring '10 term at University of Arkansas Community College at Batesville.
- Spring '10